The definition of a legal family is changing and evolving in our contemporary legal system. Many important changes are currently taking place in the development of contemporary legal systems in this sphere. Most of these involve the institution of matrimony, which no longer constitutes the sole, exclusive title on which recognition of the legal family is based. At the same time, the concept of marriage itself is changing and evolving from the past, to the point of including the union between two persons of the same sex. Complex aspects are involved in each case, which are not free from internal inconsistencies.